Filter unit for respirators



March 18, 1941. N, SCHWARTZ 2,235,624

FILTER UNIT FOR R SPIRATOR Filed July 30, 1938 INVENTOR Patented Mar.18, 1941 UNITED STATES FILTER UNIT FOR BESPIRATORS Nathan Schwartz, NewYork, N. Y., assignor to Hygeia Filtering Corporation, New York, N. Y.

Application July 30, 1938, Serial No. 222,139

3 Claims.

This invention relates to filter type respirators adapted 'to cover thenose and mouth of the wearer for the purpose of protection against dustfumes and gases, and also to provide loud speaking facilities, and is amodification of my cop i March 2, 1938, Serial No. 193,417, andapplication of February 9, 1937, Serial No. 124,851, and application ofJanuary 25, 1937, Serial No. 122,169, and application of February 6,1937, Serial No. 124,372, now Patent No. 2,114,358.

The object of this invention is to provide a simplified filter unitconstruction wherein the loss of surface filtration area is minimizedand where the parts of the said unit is easily replaceable and where theface piece has attached thereto a speaking tube containing an amplifier.

Another object is to provide a new and useful filter unit which isreadily and removably inserted into a casing adapted for the saidinsertion. The construction of the said unit is simple and permits ofvaried shapes and sizes to provide a large surface filter area in asmall casing or separator.

Another object is to provide means for loud speaking for the wearer, byhaving a speaking tube attached to the face piece.

Another object is to provide means for amplifying the sound transmittedby the said speaking tube which will be fully explained later on. v

With these and other objects in view the invention consists of certainnovel features of construction as hereinafter shown and described andthen specifically pointed out in the claims.-

In the drawing:

Figure 1 illustrates the respirator, showing the' face piece with thespeaking tube and filter holder or container attached thereto.

Figure 2 is a front view in section on line 2-2 of Figure 1.

Figure 3 is a section on line 3-3 of Figure 1. Figure 3a is like Figure3 in modified form. Figure 4: is a perspective of felt. filter unitpartly broken.

Figure 5 is a perspective of the rubber rim support.

Figure 6 is a perspective of outer plate support element.

Figure 'I is a perspective of filter support tube element.

Figure 8 is another form of this invention showing a marginal outerflange showing slits for interlocking with the edges of the outersupport plate.

Figure 9 is a section on line 89 of Figure 8.

Figure 10 is a perspective of the modified form illustratinginterlocking method at outer margin of casing.

application for Respirators, filed.

' Figure 11 is a perspective of plate support element showinginterlocking slit.

Figure 12 is a peripheral view of support plate in the modified form.

Figure 13 is another modification showing a filter pad in coveringrelation to the plate support which has apertures and in the outermarginal groove the edges of a filter pad replace the rim.

Referring to the drawing. by character of reference, A designates theface piece of the respirator, B the casing, C the filter unit, D theheadband, E the exhalation valve, F the loud speaker, G the modifiedcasing and H another modified casing.

The face piece A is preferably of molded elastic rubber or itsequivalent and has a recess in below the nose line which recess isformed by a substantially horizontal nose covering portion and anangular downwardly directed mouth covering portion 12, and a chincovering portion l3. There is an aperture I at the mouth coveringportion and an aperture 15 in the chin covering portion, and an apertureIt at the side ofthe face piece. The face piece A is a substantially cupshaped hollow mask body adapted to cover the nose, mouth, chin and partof the cheek of the wearer. The said face piece is adapted to have anexhalation valve attached at the mouth covering portion l2, and aseparator attached to the chin covering portion l3, and a speaking tubeattached at the side of the face piece.

The casing B or filter holder is preferably of a light aluminum metaland has a rear wall H, a circumferential wall 18, and an outer marginalgroove 19 which is adapted for engaging an outer disc or plate filtersupport element 20. The support element 20 is preferably of aluminummetal but may be card board or other equivalent material.

The filter unit C has filter material 2| of felt or other equivalentmaterial which may be processed cotton, paper, wool, silk-rayon or otherfabric. The filter material or pad 2i is constructed by having thefabric cut in disc like forms and stitching one to another at the mar-'ginal edges 22. There are two such pads 2| and the forward on 21a hastwo layers each with a central aperture 24 which is adapted to beattached to the supporting tube element 23. The rear filter pad 2") isconstructed like the forward one except that only one layer of the padis apertured. Namely the forward layer has an aperture 240. which isattached to the tube 23. The tube 23 has apertures'25 and 26 and anouter opening 21. The unfiltered air enters at the outer opening 21 andpasses to apertures 25 and 26 as indicated by arrows, to be filtered bythe pads 2|. and then enters the face piece by way of connectingaperture 23. The connecting aperture 23 is formed by an eyelet 30Joining the aperture Ii of the face piece and the aperture 29 which islocated in the rear wall of the casing.

The outer marginal construction of the casing may be made in threeforms. Th first form as illustrated in Figure 1 has a marginal inwardlyopening groove l3 enclosing an elastic rubber rim washer 3|, which hasan internal annular depression 32 for engaging the support disc element20. The stiff disc 20 readily engages in the depression 32 due to theelastic quality of the rim 3l.- The disc element has an aperture 33 atits central portion, which is attached to the tube 23, in adjacentposition with the filter pad 2!.

In the second form of the marginal construction, illustrated in Figures8, 9, 10, 11, and 12, the

engagement of the disc plate 20 at the groove I3 is as follows:' Thegroove l3 has an outer flange 34 which flange is provided with slits 35.Preferably four such slits 35 are provided. Also the disc plate 20 hassimilar slits 36 located at its edges. The two sets of slits are' formedto register, one with another, in an interlocking manner. The tube 23 isattached to the disc 20 at its aperture 33 and the outer extension ofthe said tube is used as a thumb rest to manipulate the disc 20 to causea proper air tight interlocking. A rubber rim washer support 3 la aidsthe said air tight formation. As the disc 20 is interlocked at its edgesthe elastic rim washer support 31a permits the interlocking andthereupon it tightens against the joint formation thereat, whereby dueto its elastic support quality, a leakprooi' Joint is provided. Therubber rim 3la engages the flange 34 of the groove I9 and extends inwardto engage the marginal portion of the plate or disc filter support 200.thereby insuring a leakproof joint.

In the 3rd form of this invention the marginal arrangement of the outercasing part of a similar interlocking construction. In this in stancethe disc filter support 20b is provided with apertures and has a filterpad 31 at its rear aspect, which pad extends into the'inwardly openinggroove Hi). This form is illustrated in Figure '13. The filter pad 31acts as a filter and also as a washer at the interlocking joint, fillingin at the interlocking slits of the flange 34 and the disc 20b. Thefilter pad 31 has a central aperture and is attached to the tube 23 atthat point, by means of cement. Otherwise the casing and filter unit islike in the two previous forms.

In Figure 3 is illustrated a speaking tube F. The tube has an innervoice receiving chamber 33, a central vacuum chamber 33 and an outertransmitting chamber 40. The tube F has an outer groove about centrallylocated to receive and engage the face piece at the side portion. Due tothe face piece being of elastic molded rubber and the rubber aperture ismade smaller than the diameter of the groove, 9. leakproof joint isprovided. Additional precaution may be had if the aperture and groove iscemented. The central vacuum chamber is formed by having an outer metaldiaphragm 42 and an inner parchment. diaphragm 43. The vacuum is formedby heating the area before cementing in situ the inner parchmentdiaphragm. A tickler or hammar 44 joins the diaphragms 42 and 43. Atransmission of the speaking voice is thus created. The voice isreceived at the chamber 38 and the said voice waves pound against thediaphragm 43 and the hammer 44 conveys the sound to the outer diaphragmwhich is carried by the outer transmitter 43. This speaking tube makesit possible for the wearer or the respirator to speak distinctly andalso loudly. While heretofore that was not possible. The voice ismuflled and indistinct when one is trying to speak with a. respiratorhaving no speaking tube provision.

Transmission of voice may be provided without the creation of a vacuumin the speaking tube. This method is simpler and also provides a goodtransmission. The arrangement of the dia-, phragms in the modified formis as follows: The tube arrangement is the same as in the first formabove'tiescribed, and the outer metal diaphragm 42a is also the same.The inner diaphragm 43a is a stiff fibrous material or may be cardboard,plastic. hard rubber or metal. As shown in Figure 3a the inner diaphragmis attached by means of a tickler or hammer to the outer diaphragm.

The said tickler 44a is centrally located and may be a wire or made ofivory or bone material. The periphery of the outer diaphragm 42a is freeof any attachments. The diaphragm 43a receives the sound wave which isamplified in the process of transmission to the outer diaphragm 42a bymeans of the tickler or hammer 44a,

It is to be noted that the tube 23 extends outwardly from the discelement 20. The purpose of the outward extension is to be able tomanipu- 1 late the disc 20 when inserting or removing the same from itsattachment with the casing at its outer marginal groove I3.

It is to be noted that the hammer 44 has a base 45 and a handle 43, andthat it is attached to the outer diaphragm at its base portion, and tothe inner disc or diaphragm at its handle part.

What is claimed is:

1. A filter holder for filter type respirators including a casing havingan intake port with filter means comprising a hollow filter pad with anaperture, a disc like filter pad having a marginal edge and an openingwhich opening registers with the said aperture, and means provided atthe said intake port whereby the said disc like pad (at its marginalportion)v is removably mounted thereat, and the said hollow pad beinglocated within the said casing rearward to the said disc like pad, itsaperture being disposed anteriorly whereby unfiltered air enters thereatduring inspiration of the wearer.

2. A separator for filter type respirator including a casing having anintake port with filter means comprising a hollow filter pad with anaperture, a tubular element for the said pad located within the saidaperture and containing an opening for air passage and means to securethe said pad to the said port comprising a supporting plate mounted inconfronting and associated relationship with the said pad and the edgesof the said plate being removably securedat the said intake port, andthe saidpad is located within the said casing.

3. A separator for filter type respirators comprising a container withan inlet aperture, a hollow filter pad with an opening; a. disc likefilter element having edges and a perforation, a tubular memberconnecting the said hollow filter pad with the said filter element bybeing mounted at the said opening and the said perforation, and the saidelement being associated in confronting relation with the said pad andmounted at the said aperture at its edge portion, and the hollow filterpad being located within the said container.

NATHAN SCHWARTZ.

